Category Archives: Nesting & Courtship

Are They Incubating?

Morela covers the egg while it rains, 18 Mar 2021 (photo from the National Aviary falconcam at Univ of Pittsburgh)

After Morela laid her first egg on St. Patrick’s Day many of you had questions about incubation. Here are some answers.

Why aren’t they sitting on the egg? Unlike bald eagles peregrines do not begin incubation until the female has laid her next-to-last egg. Only the female knows when that last egg will be. It hasn’t happened yet. Yesterday Ecco guarded instead of incubating. Click here for more details.

Ecco guarding the egg. Lots of rain (photo from the National Aviary falconcam at Univ of Pittsburgh)

If incubation has not begun, why is Morela sitting on the egg? (photo at top)

Peregrines make sure their eggs stay dry and do not freeze. Yesterday was very rainy and very windy (raindrop on screenshot). Morela was keeping the egg dry.

How will we know when incubation has begun?

Incubation is the act of raising an egg’s internal temperature and keeping it there so that the embryo inside the egg develops into a baby bird (read more here). The temperature must remain elevated for the entire incubation period; otherwise the embryo dies.

Though it appears that incubation is just the act of laying one’s chest against an egg, the egg’s temperature will not rise if there are feathers between the egg and the parent’s skin. Feathers are excellent insulation so the parent has to have a bare patch of skin called a brood patch. It develops on brooding parents for the nesting season, lightly covered with feathers that the bird moves out of the way when brooding. Here’s what a brood patch looks like on another falcon, the American kestrel.

Brood patch on a female kestrel (photo by Jared B. Clarke, Birding Saskatchewan blog)

It is hard to tell if a bird is incubating by looking at a snapshot because you cannot see whether the bird exposed its brood patch. The best way to tell is by looking at the amount of time spent on the eggs. During incubation the adults spend about 98% of the day+night on eggs. This Day-in-a-Minute shows that Morela and Ecco are not spending much time on the egg.

Based on this evidence, incubation has not begun yet at the Cathedral of Learning nest.

Watch for more eggs to come at the National Aviary falconcam at University of Pittsburgh.

p.s. What’s the advantage of delaying incubation? All the chicks hatch at once! Ducks, geese and shorebirds delay incubation, too.

(photos and video from the National Aviary falconcam at Univ of Pittsburgh)

Videos of 1st Pitt Peregrine Egg, 17 March 2021

Ecco visits the 1st egg, 17 Mar 2021, 1:23pm (photo from National Aviary falconcam at Univ of Pittsburgh)

18 March 2021

In case you missed it at the Cathedral of Learning peregrine nest: Morela laid her first egg of 2021 on 17 March at 11:50am. (Time code on the streaming camera says 11:53a but that camera is 3-4 mins early.)

The timelapse video below gives an overview of the day’s activity: Morela, Ecco and the egg.

Details of egg laying: As the next video begins Morela was standing over the scrape but is restless. She paces and squats, then Ecco arrives to bow. He watches intently while she concentrates on laying the egg. After he leaves Morela pushes (raises tail), pants and lays the egg at 11:53:45am. Notice how she makes sure not to touch the egg while it’s wet. She moves to shelter it from the sun.

Father bird’s first visit: It is always interesting to watch the father’s first visit to the egg, especially since Ecco is a first-time dad. Ecco arrived at 1:20pm, chirped at the egg, turned it, dug the scrape deeper, and sheltered the egg from the sun. He is taking an active role in the egg’s welfare.

Do not worry that the parents are not “sitting” on the egg right now. Unlike bald eagles peregrines do not begin incubation until the female has laid her next-to-last egg — and only the female knows when that egg will be.

Until incubation begins both parents guard the eggs and shelter them but will not “sit” on them to raise their temperature. They will be nearby but maybe not seen on camera.

Morela will probably lay 3-5 eggs, one every other day. If her total is four, incubation may begin on or around 21 March. We’ll have to wait and see.

Check my Peregrine FAQs for information on incubation, hatching and peregrine behavior.

Watch the action on the National Aviary falconcam at University of Pittsburgh.

(photos and videos from the National Aviary falconcam at Univ of Pittsburgh)

p.s. Terzo is gone, last seen on 5 Feb. Ecco is the only male on site.

Peregrines Are Active At Night

Morela at the Cathedral of Learning nest, 8 March 2021, 8:48pm (photo from the National Aviary at Univ of Pittsburgh)

10 March 2021

The falconcam at the Cathedral of Learning gives us a 24-hour window on the lives of the Pitt peregrines at their nest. What we see is often unique to the breeding season but one activity is probably true all year — peregrines don’t sleep through the night.

In the run-up to egg laying Morela is spending her nights perched at the front of the nestbox but it’s clear from the falconcam that she is periodically active after dark.

On the night of 8 March she fell asleep after sunset but left the nestbox at 8:50pm and returned 40 minutes later with a full crop. Since she’s not hunting for herself at this point I suspect Ecco brought her a bedtime snack.

Morela with a full crop, 8 March 2021, 9:44pm (photo from the National Aviary at Univ of Pittsburgh)

Morela left the nest again at 4am and within half an hour Ecco showed up and called to her. Was he courting her at night?

Watch the Day-in-a-Minute video below, 8 March 4:20pm to 9 March 7:00am to see what our peregrines are up to on a typical March night.

By the way, this isn’t the first time we’ve seen this on camera. In April 2010 Louie and Dori were active at night at the Gulf Tower nest.

Watch the live action for yourself at the National Aviary’s falconcam at Univ of Pittsburgh.

(photos and videos from the National Aviary’s falconcam at Univ of Pittsburgh)

Getting Closer to Nesting

Morela roosts at the green perch overnight, 3-4 March 2021 (photo from the National Aviary snapshot camera at Univ of Pittsburgh)

4 March 2021

As nesting time approaches female birds roost near their intended nest in anticipation of egg laying.  In a positive development at the Pitt peregrine nest, Morela spent much of last night perched at the front of the nestbox.

Morela’s nighttime sojourn began when she and Ecco bowed at 6pm.

Then Morela fell asleep on the green perch for six hours.

I’ll bet no one was watching when she woke up just before midnight and left the camera view. She returned at 5:30am and stayed until the sky began to lighten at 6:17a, the start of civil twilight.

I learned all this by watching the 24-hour timelapse below which compresses 24 hours into two minutes (7am March 3rd – 7am March 4th). In it Ecco and Morela go back and forth to the nest, first Ecco then Morela. They mirror each other’s movements. Ecco even preens on the green perch. Can you tell who is who?

Tomorrow it will be a month since Terzo was last seen on camera. Today Ecco and Morela are still the only two peregrines at Pitt and they are getting closer to nesting. Watch them on the National Aviary falconcam at Univ of Pittsburgh.

(photo and video from the National Aviary falconcam at Univ of Pittsburgh)

Courtship With Food

Morela takes Ecco’s offering, 26 Feb 2021, 10:11a (photo from the National Aviary falconcam at Univ of Pittsburgh)

28 February 2021

One of the rituals of peregrine courtship is that the male must bring food to the female to show he can provide for her and their family. As egg laying time approaches the female stops hunting for herself; her mate provides all her food. She won’t resume hunting until the nestlings are old enough to leave for a while.

Courtship is well underway at the Cathedral of Learning nest. On Friday morning, 26 February, Ecco brought prey to the ledge (the green perch) and waited for Morela. He ate some while he waited, then called to Morela when he saw her overhead. Eventually she came in to take his offering.

In the video below, watch the strip of sunlight on the back wall of the nest and you’ll see Morela’s shadow as she lands above him.

Courtship will intensify in March with the possibility of eggs by month’s end. Watch the Cathedral of Learning peregrines on the National Aviary falconcam at the University of Pittsburgh.

Want to learn more about peregrine behavior? Read about peregrine Courtship feeding here and lots more at my Peregrine FAQs (Frequently Asked Questions).

(photos and video from the National Aviary falconcam at Univ of Pittsburgh)

Identifying Ecco and Morela

  • Ecco, male (21 Feb 2021, 9:13)

22 February 2021

The unbanded male peregrine, Ecco, has been present every day at the Cathedral of Learning since 4 February — 19 days in a row — while the former resident male, Terzo, has not been seen since 5 February. With this kind of track record I believe that Ecco has won the site and is now the resident male.

Now that Ecco is present every day and neither he nor his mate Morela are banded how do we tell them apart? Here are some tips, photos and videos to help you compare and identify each bird.

Size: Male peregrines are 1/3 smaller than females. The slideshows display Ecco and Morela in similar poses. Morela is always the bigger bird. Check the captions if you are unsure.

  • Ecco

The easiest way to determine size is to compare the bird to the size of the enclosure or camera view. How long is the bird compared to the available space? Morela is longer. Does the bird look bulky? Morela is bulkier.

Coloration: Morela’s breast and face are peach-colored where Ecco is white.

The videos below will give you practice identifying them on camera.

Ecco alone at the nest, 21 Feb 2021

Morela alone at the nest, 21 Feb 2021

The more we watch them the better we’ll get at identifying each one. My hope is that Ecco and Morela stay at the Cathedral of Learning for many years to come.

(photos and videos from the National Aviary falconcam at Univ of Pittsburgh)

Raccoon Redux

Bald eagle pair scares off raccoon approaching their nest, 17 Feb 2021 (screenshot from PixCams on YouTube)

19 February 2021

On Wednesday night, 17 February just after 7pm, a raccoon scaled one of the branches that holds the Hays bald eagle nest. The mother eagle was on the nest and heard the raccoon coming so she rose up, spread her wings, and scared him away.

Seven years ago a raccoon intruder did the same thing. This one was a little braver.

The raccoon hid nearby, frozen in place, but four minutes later he moved again and the father eagle arrived to help. Two eagles!! The raccoon finally left.

This week’s episode was a raccoon redux of …

See Mary Ann Thomas’ Trib Live report, Pittsburgh Hays Bald Eagles Attack Raccoon Intruder, with video of Wednesday’s raccoon leaving.

Watch the Hays Nest Eaglecam to see what happens next.

(screenshot from PixCams on YouTube)

UPDATE, 19 Feb 2021: The female bald eagle at Hays laid her 3rd egg on 19 February 2021.

UPDATE, 22 Feb 2021: On the night of 22 Feb 2021 a great horned owl knocked the male Hays bald eagle off his roosting perch. The eagle was surprised but unharmed.

Everyone’s Enemy

Great horned owl at Frick Park, April 2019 (photo by Steve Gosser)

16 February 2021

Most birds fear great horned owls (Bubo virginianus) for they are such top predators that they will eat the young of bald eagles, peregrine falcons and red-tailed hawks.

Their nesting habits are dangerous, too. Like other owls they never build a nest but great horned owls will steal one that looks good to them. They usually pick on red-tailed hawks. It leads to a fight as shown in the video below.

In early February 2019 a red-tailed hawk was building a nest at Presidio park in San Francisco when a great horned owl decided to steal it. The details of their encounter are quoted below the video. (Abbreviations: RTH=red-tailed hawk, GHO=great horned owl)

A pair of great horned owls have been visiting this red-tail hawk nest at the Presidio for several nights. This is the first time it’s come to the nest during the day, and the first time the RTH has seen it. It didn’t take kindly to the invasion and attacked it soon after it arrived. The GHO was able to fend off the RTH the first time, but in the 2nd attempt, it falls off the nest and doesn’t come back….until the next day. The RTH returns to make sure all is secure. Confrontations done in real time and SloMo. NOTE: The owl comes back the next day & lays an egg, and another a few days later. There are a few minor skirmishes, but the RTH finally moves on & lets the GHO have the nest. One of its two eggs broke, but the remaining egg is due to hatch mid-March. UPDATE: The 2nd egg failed to hatch also. The owl eventually moved on.

description of owl vs red-tail video on Janntonne’s channel on YouTube

If the owls are persistent, the red-tailed hawks eventually give up. Great horned owls outweigh red-tails by 30% and their talons are more than twice as powerful with a talon strength of 500 lbs per square inch. On the glove you can see the difference: red-tailed hawk (left), a great horned owl (right).

Here’s a comparison of their talons: red-tailed hawk on left, great horned owl on right (photos by Kate St. John at Medina Raptor Center, Ohio, Nov 2014)

Everyone’s enemy is a formidable foe. No nest is worth dying for.

p.s. It is likely that Pittsburgh’s great horned owls have already laid eggs — much earlier than bald eagles, red-tailed hawks and peregrines According to the Breeding Bird Atlas of Pennsylvania the earliest egg dates in PA are …

  • Great horned owl = 22 January
  • Bald eagle = 6 February
  • Red-tailed hawk = 24 February
  • Peregrine falcon in Pittsburgh = 6 March (based on falconcam at Pitt)

(owl photo by Steve Gosser, talon photos by Kate St. John)

UPDATE: On the night of 22 Feb 2021 a great horned owl knocked the male Hays bald eagle off his roosting perch. The eagle was surprised but unharmed.

Hays Bald Eagles Have a Happy Valentine’s Day

First egg of 2021 at Hays bald eagle nest, 12 Feb 2021, 5:55pm (snapshot from ASWP’s Pittsburgh Eagles Facebook page)

14 February 2021

The Hays bald eagles are having a Happy Valentine’s Day with their first egg of the season just 36 hours old. The female laid her first egg on Friday 12 February 2021 at approximately 5:55pm. Their happy event was on the CBS Local news, at Trib-Live, and captured on the streaming cam on YouTube.

The female usually lays her second egg three days after the first so watch the Hays Nest Eaglecam tomorrow, 15 February, for the arrival of another egg.

Catch up on all the Hays Bald Eagle news at ASWP’s Pittsburgh Eagles Facebook page.

Happy Valentine’s Day!

(photo and video from ASWP’s Hays Eaglecam)